Blincyto spurs the body's immune system to fight the disease, the FDA said Wednesday in a news release. It's the first approved drug that engages the body's disease-fighting T-cells to destroy leukemia cells. The drug is sanctioned for people who have tried at least one previous therapy or who have seen their cancer return. The drug's safety and effectiveness were evaluated in a clinical study involving 185 adults with the disease. After at least four weeks of treatment, 32 percent of participants had no evidence of the cancer for about six months.

"Immunotherapies, especially Blincyto with its unique mechanism of action, are particularly promising for patients with leukemia," Richard Pazdur, M.D., director of the Office of Hematology and Oncology Products in the FDA's Center for Drug Evaluation and Research, said in an agency news release.

Blincyto's label includes a boxed warning that some clinical trial participants had low blood pressure and difficulty breathing, or had nervous system impairment such as difficulty thinking, the FDA said. More common side effects included fever, headache, peripheral edema, febrile neutropenia, nausea, hypokalaemia, fatigue, constipation, diarrhea, and tremor.